Drive device and method of manufacturing the same

ABSTRACT

A drive device includes a motor, a connector on which a control board is mounted, and a cover that defines a housing space for the control board together with the motor and the connector. A first recess formed on a first side of the motor and having an annular shape is connected by a first adhesive to a first protrusion formed on a mounting side of the connector. A second recess formed on a connection side of the connector and having an annular shape is connected by a second adhesive to a second protrusion formed on a rim side of the cover. Therefore, the motor and the cover are connected through the connector.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2019-093611 filed on May 17, 2019.

TECHNICAL FIELD

The present disclosure relates to a drive device that includes an electric motor, a control board, a connector, and a cover, and a method of manufacturing the drive device.

BACKGROUND

A general drive device includes a housing and an electric motor. The housing is joined to the electric motor by screwing.

The housing of the drive device includes a casing member and a cover member. A gap between the casing member and the cover member is filled with sealant.

SUMMARY

A drive device according to one aspect of the present disclosure includes: a motor; a connector on which a control board configured to control the motor is mounted; a cover that defines a housing space for the control board together with the motor and the connector; a first adhesive that connects the motor and the connector; and a second adhesive that connects the connector and the cover. The motor, the connector, and the cover are stacked with each other in a predetermined direction. The connector is between the motor and the cover in the predetermined direction. The motor has a first side on which the connector is mounted. The first side of the motor has a first recess recessed in the predetermined direction, the first recess having an annular shape that surrounds an imaginary line extending along the predetermined direction. The connector has a mounting side facing the motor. The mounting side of the connector has a first protrusion protruding toward the motor in the predetermined direction, the first protrusion having an annular shape corresponding to the first recess. The connector has a connection side facing the cover. The connection side of the connector has a second recess recessed in the predetermined direction, the second recess having an annular shape that surrounds the imaginary line extending along the predetermined direction. The cover has a rim side facing the connector. The rim side of the cover has a second protrusion protruding toward the connector in the predetermined direction, the second protrusion having an annular shape corresponding to the second recess. The first protrusion is inserted into the first recess. The first protrusion and the first recess are connected over an entire circumference of the first recess by the first adhesive. The second protrusion is inserted into the second recess. The second protrusion and the second recess are connected over an entire circumference of the second recess by the second adhesive.

According to another aspect of the present disclosure, a method of manufacturing a drive device includes: placing the motor such that a first side of the motor on which the connector is to be mounted is positioned above a second side of the motor in a vertical direction; applying the first adhesive in liquid phase to a first recess formed on the first side of the motor, the first recess being recessed downward in the vertical direction and having an annular shape that surrounds an imaginary line extending along the vertical direction; inserting a first protrusion formed on a mounting side of the connector into the first recess, the first protrusion protruding downward in the vertical direction and having an annular shape corresponding to the first recess, and thereby the first protrusion and the first recess are connected over an entire circumference of the first recess by the first adhesive; applying the second adhesive in liquid phase to a second recess formed on a connection side of the connector that is an opposite side of the mounting side in the vertical direction, the second recess being recessed downward in the vertical direction and having an annular shape that surrounds the imaginary line extending along the vertical direction; and inserting a second protrusion formed on a rim side of the cover into the second recess, the second protrusion protruding downward in the vertical direction and having an annular shape corresponding to the second recess, and thereby the second protrusion and the second recess are connected over an entire circumference of the second recess by the second adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a steering system.

FIG. 2 is a top view of a drive device.

FIG. 3 is a side view of a drive device.

FIG. 4 is a cross-sectional diagram taken along IV-IV line of FIG. 2.

FIG. 5 is a top view of a motor.

FIG. 6 is an exploded side view of the drive device.

FIG. 7 is a top view of a control board.

FIG. 8 is a bottom view of a connector.

FIG. 9 is a top view of the connector.

FIG. 10 is a bottom view of a cover.

FIG. 11 is an enlarged cross-sectional view of a region A surrounded by a dashed line shown in FIG. 4.

FIG. 12 is a cross-sectional diagram showing a first recess filled with a first adhesive and a first protrusion facing with each other.

FIG. 13 is a cross-sectional diagram showing a second recess filled with a second adhesive and a second protrusion facing with each other.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described hereinafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

Comparative Example

In a drive device of a comparative example of the present disclosure, the gap between the casing member and the cover member is filled with sealant. However, the housing and the electric motor are simply joined by screwing. Accordingly, the sealing properties might be weak.

It is an object of the present disclosure is to provide a drive device with improved sealing properties and a method of manufacturing the drive device.

First Embodiment

An electric power steering device to which a drive device according to the present embodiment is applied will be described with reference to FIGS. 1 to 13.

<Steering System>

As shown in FIG. 1, the electric power steering device 200 is used for a steering system 100 of a vehicle. The steering system 100 includes a steering wheel 110, a steering shaft 120, a pinion gear 130, a rack shaft 140, wheels 150, and the electric power steering device 200.

The steering wheel 110 is connected to the steering shaft 120. A pinion gear 130 is provided at an end of the steering shaft 120. The pinion gear 130 meshes with the rack shaft 140. A pair of road wheels 150 is connected to both ends of the rack shaft 140 via tie rods or the like.

When a driver turns the steering wheel 110, the steering shaft 120 connected to the steering wheel 110 rotates. A rotational motion of the steering shaft 120 is converted into a linear motion of the rack shaft 140 by the pinion gear 130. As a result, the pair of wheels 150 are steered to an angle corresponding to the amount of displacement of the rack shaft 140.

<Electric Power Steering Device>

The electric power steering device 200 has a function of assisting the turn of the steering wheel 110. The electric power steering device 200 includes a torque sensor 210, a reduction gear 220, and a drive device 300 as shown in FIG. 1. The drive device 300 includes a motor 310 and a controller 350.

The torque sensor 210 is configured to detect a steering torque of the steering shaft 120. The steering torque detected by the torque sensor 210 is input to the controller 350.

The controller 350 is configured to control the actuation of the motor 310 based on the steering torque detected by the torque sensor 210, signals input from ECUs mounted on the vehicle, and the like.

The motor 310 is connected to the reduction gear 220 through a belt (not shown). The reduction gear 220 decelerates the rotation of the motor 310 and transmits it to the steering shaft 120. Accordingly, the turn (steering) of the steering wheel 110 is assisted.

The electric power steering device 200 of the present embodiment is a column assist electric power steering device that provides an assist force to the steering shaft 120 for assisting the steering. However, the configuration of the electric power steering device 200 is not limited to the above-described example. The electric power steering device 200 may be a rack assist electric power steering device that provides an assist force to the rack shaft 140 or a pinion assist electric power steering device that provides an assist force to the pinion gear 130.

<Drive Device>

The drive device 300 will be described next. Hereinafter, three directions orthogonal to each other are referred to as an X-direction, a Y-direction, and a Z-direction. The Z-direction corresponds to a predetermined direction.

The drive device 300 includes the motor 310 and the controller 350 as described above. As shown in FIGS. 2, 3, the motor 310 and the controller 350 are arranged in the Z-direction and connected with each other. The drive device 300 has so called machine-electronic integrated structure.

<Motor>

As simply illustrated in FIG. 4, the motor 310 includes a motor shaft 311, a rotor 312, a stator 313, and a housing 314. The housing 314 has a circular cylindrical shape whose axial direction is the Z-direction. The motor shaft 311, the rotor 312, and the stator 313 are housed in the housing 314. The motor 310 corresponds to the electric motor.

The motor shaft 311 extends in the Z-direction. The rotor 312 is fitted in the center of the motor shaft 311. The stator 313 surrounds the rotor 312 and is housed in the housing 314. Rotational torque is generated on the motor shaft 311 by magnetic fields emitted from the rotor 312 and the stator 313. Thereby, the motor shaft 311 rotates.

The stator 313 of the present embodiment has two windings. Each of the two windings includes a three-phase (U, V, W) stator coil that constitutes a brushless motor. Six motor wires 315 for supplying three-phase electric power to the three phase stator coil having two windings extend in the Z-direction from the housing 314 toward the controller 350.

As described above, the housing 314 has a circular cylindrical shape. The housing 314 has a first end side 314 a and a second end side 314 b which face in the Z-direction, and a lateral side 314 c connecting these end sides. The first end side 314 a corresponds to a first side. The second end side 314 b corresponds to a second side.

As shown in FIGS. 4-6, each end of the six motor wires 315 connected to the three-phase stator coil protrudes out of the housing 314 from the first end side 314 a. The ends of the motor wires 315 are connected to a control board 360 described later. One end of the motor shaft 311 protrudes out of the housing 314 from the second end side 314 b, as shown in FIGS. 3, 4. The one end of the motor shaft 311 is connected to the reduction gear 220 through a belt.

As shown in FIG. 5, the first end side 314 a has a circular shape in a plane facing the Z-direction. The first end side 314 a has bolt holes 314 d for fixing a connector 370 to the housing 314 as well as holes through which the end of the motor wire 315 passes.

In the present embodiment, three bolt holes 314 d open on the first end side 314 a. The three bolt holes 314 d are located on a circumference of a circle whose center is the center of the first end side 314 a. The three bolt holes are arranged at intervals of 120 degrees.

A first recess 316 recessed in the Z-direction is formed on the rim of the first end side 314 a as shown in FIGS. 4, 5. The first recess 316 has an annular shape about a line along the Z-direction. The first recess 316 is filled with a first adhesive 391 as shown in FIG. 11. The housing 314 and the connector 370 are connected by the first adhesive 391.

<Controller>

The controller 350 includes the control board 360, the connector 370, and a cover 380 as shown in FIGS. 4, 6. The control board 360 is fixed to the housing 314 through the connector 370. The cover 380 is fixed to the connector 370. Since the housing 314 and the cover 380 are fixed through the connector 370, a housing space for the control board 360 is defined. The motor 310 and the cover 380 are stacked with each other through the connector 370. That is, the motor 310, the connector 370, and the cover 380 are stacked with each other, and the connector 370 is between the motor 310 and the cover 380 in the Z-direction.

<Control Board>

The control board 360 has a wiring board having a plate shape that is thin in the Z-direction. Active elements such as MOSFET and passive elements such as condenser are mounted on the wiring board. The control board 360 includes a microcontroller, a gate driver, an inverter, and the like for controlling the motor 310 which are constituted by a wiring pattern of the wiring board, the active elements, and the passive elements.

The control board 360 has an upper side 360 a and a lower side 360 b in the Z-direction as shown in FIGS. 6, 7. The control board 360 is mounted on the connector 370 such that a part of the lower side 360 b is spaced in the Z-direction from the first end side 314 a of the housing 314. The lower side 360 b faces in the Z-direction.

The control board 360 has multiple holes that open on the upper side 360 a and the lower side 360 b. Specifically, the control board 360 has motor holes 361, sensor holes 362, and communication holes 363.

The motor wire 315 passes through the motor hole 361. A sensor pin 375 electrically connected with the torque sensor 210 passes through the sensor hole 362. A communication pin 376 for communicating with the ECUs mounted on the vehicle passes through the communication hole 363. The motor wire 315, the sensor pin 375, and the communication pin 376 are bonded to the control board 360 by soldering.

The control board 360 further has a power hole through which a power pin (not shown) for electrically connecting with the battery passes. The power pin is also bonded to the control board 360 by soldering.

The control board 360 further has a bolt through-hole 364 and positioning holes 365. The shank of the bolt fastened to the bolt hole 314 d passes through the bolt through-hole 364. A protrusion 377 b described later passes through the positioning hole 365. As shown in FIG. 7, the control board 360 has two positioning holes 365. The positioning holes 365 are spaced from each other in the X-direction and the Y-direction.

<Connector>

Specifically, the connector 370 has a base portion 371 and a connection portion 372 as shown in FIGS. 8, 9.

The base portion 371 has an annular shape opening in the Z-direction. That is, the connector 370 may have a cylindrical shape. The base portion 371 has an inner annular surface 371 a and an outer annular surface 371 b having an annular shape about a line along the Z-direction. The base portion 371 has an upper support surface 371 c and a lower support surface 371 d connecting the two annular surfaces. The upper support surface 371 c and the lower support surface 371 d are aligned in the Z-direction.

A first protrusion 373 protrudes from a rim of the lower support surface 371 d in the Z-direction as shown in FIGS. 4, 8. The first protrusion 373 has an annular shape about a line along the Z-direction. The lower support surface 371 d is a mounting side.

The first protrusion 373 is inserted into the first recess 316 of the housing 314 as shown in FIG. 11. The first protrusion 373 and the first recess 316 are connected by the first adhesive 391. The gap between the first protrusion 373 and the first recess 316 is filled by the first adhesive 391. Accordingly, the gap between the connector 370 and the motor 310 is sealed by the first adhesive 391.

The connection portion 372 extends from a part of the outer annular surface 371 b of the base portion 371 in the Y-direction. When the base portion 371 is fixed to the first end side 314 a of the housing 314, the connection portion 372 does not face the first end side 314 a in the Z-direction.

The sensor pin 375, the communication pin 376, and the power pin are formed in the connection portion 372 by insert molding. Ends of each of these three pins are exposed from the connection portion 372.

The connection portion 372 has a first connection surface 372 a and a second connection surface 372 b aligned in the Z-direction as shown in FIGS. 8, 9. One end of each of the three pins protrudes in the Z-direction from the first connection surface 372 a and is connected to the control board 360. The other end of each of the three pins protrudes from the second connection surface 372 b and is connected to a wire harness (not shown). Accordingly, the control board 360 is electrically connected with the torque sensor 210, the ECUs, and the battery mounted on the vehicle.

A second recess 374 recessed in the Z-direction toward the lower support surface 371 d is formed on a rim of the upper support surface 371 c of the base portion 371 as shown in FIGS. 4, 9. The second recess 374 recessed in the Z-direction toward the second connection surface 372 b is also formed on a rim of the first connection surface 372 a of the connection portion 372. The upper support surface 371 c and the first connection surface 372 a are connection sides.

The second recesses formed in the base portion 371 and the connection portion 372 are continuous to form an annular shape about a line along the Z-direction. The second recess 374 is filled with a second adhesive 392 as shown in FIG. 11. The base portion 371 and the cover 380 are physically connected with each other through the second adhesive 392.

As well as the base portion 371 and the connection portion 372, the connector 370 has support portions 377, guide portions 378, and flange portions 379 which are joined with the base portion 371.

The support portion 377 supports the control board 360. The support portions 377 are integrally provided with the inner annular surface 371 a or the outer annular surface 371 b. The support portion 377 formed on the inner annular surface 371 a is positioned inside a disk-shaped space surrounded by the inner annular surface 371 a. The support portion 377 formed on the outer annular surface 371 b is positioned outside the disk-shaped space surrounded by the inner annular surface 371 a.

The support portions 377 protrude in the Z-direction from the lower support surface 371 d toward the upper support surface 371 c as shown in FIG. 6. Each of the support portions 377 has a support surface 377 a facing in the Z-direction. The support surface 377 a is farther from the lower support surface in the Z-direction than the upper support surface 371 c is from. Accordingly, the support surface 377 a is located upward in the Z-direction compared to the upper support surface 371 c.

In the present embodiment, two support portions 377 are formed on the inner annular surface 371 a and the outer annular surface 371 b respectively. The two support portions 377 formed on the inner annular surface 371 a are spaced in the Y-direction from the two support portions 377 formed on the outer annular surface 371 b. The two support portions 377 formed on the inner annular surface 371 a are spaced from each other in the X-direction. The two support portions 377 formed on the outer annular surface 371 b are spaced from each other in the X-direction. The support surface 377 a of each of the four support portions 377 faces in the Z-direction. The positions of the four support surfaces 377 a in the Z-direction are equal.

One of the two support portions 377 formed on the inner annular surface 371 a has a protrusion 377 b further protruding in the Z-direction from the support surface 377 a. One of the two support portion 377 formed on the outer annular surface 371 b has a protrusion 377 b further protruding in the Z-direction from the support surface 377 a. The two protrusions 377 b are spaced from each other in the X-direction and the Y-direction to be opposite points of the inner annular surface 371 a.

When the control board 360 is mounted on the connector 370 as shown in FIG. 6, the support surfaces 377 a of the support portions 377 contact the lower side 360 b of the control board 360. At the same time, the two protrusions 377 b are inserted into the positioning holes 365 of the control board 360 respectively.

Accordingly, the control board 360 is supported by the base portion 371 such that the control board 360 is spaced from the upper support surface 371 c in the Z-direction. Moreover, relative displacement between the connector 370 and the control board 360 in a direction intersecting the Z-direction is suppressed.

The guide portion 378 is positioned inside a disk-shaped space surrounded by the inner annular surface 371 a. The guide portion 378 has guide holes 378 c extending through the guide portion 378 in the Z-direction.

In the present embodiment, two guide portions 378 are connected to the inner annular surface 371 a. The two guide portions 378 are spaced from each other in the X-direction to be located at opposite points of the inner annular surface 371 a.

Each of the two guide portions 378 has three guide holes 378 c. The three guide holes 378 c are aligned in the Y-direction. Six motor wires 315 are inserted into the six guide holes 378 c respectively.

The guide portion 378 has an upper side 378 a and a lower side 378 b aligned in the Z-direction. The upper side 378 a is closer to the upper support surface 371 c in the Z-direction than the lower side 378 b is to. The lower side 378 b is closer to the lower support surface 371 d in the Z-direction than the upper side 378 a is to. The guide holes 378 c open on both of the upper side 378 a and the lower side 378 b.

The upper side 378 a is farther from the lower support surface 371 d in the Z-direction than the upper support surface 371 c is from. Accordingly, the upper side 378 a is located upward in the Z-direction compared to the upper support surface 371 c. The upper side 378 a of the guide portion 378 is located outside the disk-shaped spaced surrounded by the inner annular surface 371 a.

The upper side 378 a is closer to the upper support surface 371 c in the Z-direction than the support surface 377 a of the support portion 377 is to. Accordingly, the upper side 378 a is spaced from the support surface 377 a in the Z-direction.

As described above, the control board 360 is mounted on the connector 370 such that the lower side 360 b is in contact with the support surface 377 a. In this situation, the lower side 360 b is spaced from the upper side 378 a in the Z-direction. Specifically, the opening of the motor hole 361 on the lower side 360 b and the opening of the guide hole 378 c on the upper side 378 a are spaced from and aligned with each other in the Z-direction.

The lower side 378 b is closer to the upper support surface 371 c in the Z-direction than the lower support surface 371 d is to. Accordingly, the lower side 378 b is located upward in the Z-direction compared to the lower support surface 371 d.

An inner radius of the opening of the guide hole 378 c on the lower side 378 b is larger than an inner radius of the opening of the guide hole 378 c on the upper side 378 a. That is, the guide hole 378 c is tapered from the lower side 378 b toward the upper side 378 a.

The motor wire 315 is inserted into the guide hole 378 c from the opening on the lower side 378 b. The end of the motor wire 315 protrudes from the opening of the guide hole 378 c on the upper side 378 a toward the lower side 360 b of the control board 360.

The end of the motor wire 315 is inserted into the motor hole 361 from the opening on the lower side 360 b. The end of the motor wire 315 protrudes upward from the opening of the motor hole 361 on the upper side 360 a.

The motor wire 315 is bonded to the control board 360 by soldering. The solder sticks to the rim of the motor hole 361 on the upper side 360 a, the inner surface of the motor hole 361, and the rim of the motor hole 361 on the lower side 360 b. A fillet of the solder is formed on each of the upper side 360 a and the lower side 360 b.

The flange portion 379 is positioned inside a disk-shaped space surrounded by the inner annular surface 371 a. The flange portion 379 has a through-hole extending through the flange portion 379 in the Z-direction.

In the present embodiment, three flange portions 379 are connected to the inner annular surface 371 a. The through-holes 379 c formed in the three flange portions 379 are located on a circumference of a circle whose center is the center of the base portion 371. The three through-holes 379 c are arranged at intervals of 120 degrees.

The shank of the bolt passes through the through-hole 379 c. The end of the bolt is fastened to the bolt hole 314 d. The flange portion 379 is clamped between the head of the bolt and the first end side 314 a of the housing 314. Accordingly, the connector 370 is fixed to the motor 310.

<Cover>

The cover 380 has a top plate 381 and a side wall 382. The top plate 381 has a flat shape whose thickness in the Z-direction is thin. The top plate 381 has an inner surface 381 a and an outer surface 381 b aligned in the Z-direction.

The side wall 382 protrudes from the rim of the inner surface 381 a in the Z-direction. The side wall 382 has an annular shape surrounding the inner surface 381 a.

The side wall 382 has an annular end 382 b spaced from the inner surface 381 a in the Z-direction as shown in FIGS. 4, 10. The annular end 382 b has a second protrusion 383 protruding in the Z-direction. The second protrusion 383 has an annular shape about an imaginary line along the Z-direction. The end 382 b is a rim side.

The second protrusion 383 is inserted into the second recess 374 of the connector 370 as shown in FIG. 11. The second protrusion 383 and the second recess 374 are connected by the second adhesive 392. The gap between the second protrusion 383 and the second recess 374 is sealed by the second adhesive 392. Accordingly, the gap between the connector 370 and the cover 380 is sealed by the second adhesive 392.

<Method of Manufacturing Drive Device>

First, the motor 310 is provided as shown in FIG. 6. Then the motor 310 is placed (positioned) such that the second end side 314 b is positioned below the first end side 314 a in a vertical direction. The motor 310 in this state is fixed by a jig or the like.

Next, the control board 360 and the connector 370 are prepared. The lower side 360 b of the control board 360 is brought into contact with the support surface 377 a of the support portion 377 of the connector 370. At the same time, the protrusion 377 b protruding from the support surface 377 a is inserted into the positioning hole 365 opening on the lower side 360 b. Thereby, the position of the control board 360 relative to the connector 370 is temporarily fixed. The sensor pin 375, the communication pin 376, and the power pin are inserted into and soldered to the sensor hole 362, the communication hole 363, and the power hole of the control board 360 respectively.

As a result of the fixation of the control board 360 to the connector 370, the bolt through-hole 364 of the control board 360 and the through-hole 379 c of the flange portion 379 are aligned in the Z-direction. The motor hole 361 and the guide hole 378 c are aligned in the Z-direction.

Although three through-holes 379 c are formed, the number of the bolt through-hole 364 is one. Two through-holes 379 c which are not aligned with the bolt through-hole 364 in the Z-direction do not overlap the control board 360 in the Z-direction. The inner radius of the bolt through-hole 364 is larger than that of the through-hole 379 c.

Next, the connector 370 to which the control board 360 is fixed is positioned on the first end side 314 a of the housing 314. At the same time, the first adhesive 391 in the liquid phase is applied to the first recess 316 as shown in FIG. 12. The first recess 316 is filled with the first adhesive 391 in the liquid phase.

At this time, the motor wire 315 is inserted into the guide hole 378 c from the opening on the lower side 378 b. The motor wire 315 is also inserted into the motor hole 361 from the opening on the lower side 360 b. Accordingly, the end of the motor wire 315 protrudes upward from the opening of the motor hole 361 on the upper side 360 a.

The first protrusion 373 is inserted into the first recess 316 filled with the first adhesive 391 in the liquid phase as shown in FIG. 13. Accordingly, the first adhesive 391 filled in the first recess 316 overflows from the first recess 316. The gap between the first protrusion 373 and the first recess 316 is filled with the first adhesive 391.

As described above, when the connector 370 to which the control board 360 is fixed is positioned relative to the motor 310, the bolt through-hole 364, the through-hole 379 c, and the bolt hole 314 d are aligned in the Z-direction. The shank of the bolt is inserted into three or two of these holes aligned in the Z-direction. The end of the bolt is fastened to the bolt hole 314 d. The flange portion 379 is clamped between the head of the bolt and the first end side 314 a of the housing 314. As a result, the connector 370 and the motor 310 are fixed.

Subsequently, the end of the motor wire 315 protruding upward from the opening of the motor hole 361 on the upper side 360 a is removed. The motor wire 315 is bonded to the control board 360 by soldering on the upper side 360 a.

As described above, the control board 360 is fixed to the connector 370 such that the lower side 360 b is in contact with the support surface 377 a. The opening of the motor hole 361 on the lower side 360 b is spaced in the Z-direction from the upper side 378 a on which the guide hole 378 c opens.

When the motor wire 315 is bonded to the control board 360 on the upper side 360 a, the melted solder flows through the motor hole 361 from the upper side 360 a to the lower side 360 b. As a result, the solder extends from the upper side 360 a to the lower side 360 b through the motor hole 361. The fillets of the solder are formed not only on the upper side 360 a but also on the lower side 360 b. The lower side 360 b of the control board 360 and the upper side 378 a of the guide portion 378 are spaced in the Z-direction from each other such that the formation of the solder fillet on the lower side 360 b is not limited.

Next, the cover 380 is positioned above the upper support surface 371 c of the connector 370. At the same time, the second adhesive 392 in the liquid phase is applied to the second recess 374 as shown in FIG. 13. The second recess 374 is filled with the second adhesive 392 in the liquid phase.

The second protrusion 383 is inserted into the second recess 374 filled with the second adhesive 392 in the liquid phase as shown in FIG. 11. Accordingly, the second adhesive 392 filled in the second recess 374 overflows from the second recess 374. The gap between the second protrusion 383 and the second recess 374 is filled with the second adhesive 392.

Through the above steps, the cover 380 is fixed to the motor 310 through the connector 370. The control board 360 is housed in the housing space defined by the motor 310, the connector 370, and the cover 380. Parts of the control board 360 for electrical connection with the motor 310 and the connector 370 are housed in the housing space.

<Connection Between First Recess and First Protrusion>

Next, the connection between the first recess 316 of the motor 310 and the first protrusion 373 of the connector 370 through the first adhesive 391 will be described. A radial direction is defined as a direction away from a central axis passing through each center of the first end side 314 a, the lower support surface 371 d, and the upper support surface 371 c in the Z-direction.

The first recess 316 is defined between an inner wall 317 and an outer wall 318 as shown in FIG. 11. The inner wall 317 and the outer wall 318 are aligned and spaced from each other in the radial direction. Each of these walls has an annular shape. The inner wall 317 has an inner wall surface 317 a, and the outer wall 318 has an outer wall surface 318 a. The inner wall surface 317 a and the outer wall surface 318 a are spaced from each other in the radial direction. The inner wall surface 317 a and the outer wall surface 318 a face each other in the radial direction. The first recess 316 is defined by the inner wall surface 317 a, the outer wall surface 318 a, and a bottom wall surface 314 e connecting the inner wall surface 317 a and the outer wall surface 318 a. The bottom wall surface 314 e is a part of the first end side 314 a.

The inner wall 317 is closer to the central axis in the radial direction than the outer wall 318 is to. The inner wall 317 extends in the Z-direction to be taller than the outer wall 318. The inner wall surface 317 a extends in the Z-direction to be longer than the outer wall surface 318 a. Accordingly, an end of the inner wall surface 317 a does not overlap the outer wall surface 318 a in the radial direction.

The first protrusion 373 includes a first lateral surface 373 a, a second lateral surface 373 b, and a first tip surface 373 c connecting the first lateral surface 373 a and the second lateral surface 373 b. The first lateral surface 373 a and the second lateral surface 373 b are aligned in the radial direction. Each of these lateral surfaces has an annular shape. The first lateral surface 373 a is closer to the central axis in the radial direction than the second lateral surface 373 b is to.

The thickness between the first lateral surface 373 a and the second lateral surface 373 b in the radial direction is constant on the first tip surface 373 c side, but changes on the lower support surface 371 d side. That is, on the lower support surface 371 d side, the second lateral surface 373 b is inclined away from the first lateral surface 373 a such that the thickness between the first lateral surface 373 a and the second lateral surface 373 b gradually increases toward the lower support surface 371 d in the Z-direction.

The first lateral surface 373 a and the second lateral surface 373 b are farther from the central axis in the radial direction than the inner wall surface 317 a of the first recess 316 is from. The first lateral surface 373 a and the second lateral surface 373 b are closer to the central axis in the radial direction than the outer wall surface 318 a is to.

When the first protrusion 373 is inserted into the first recess 316 filled with the first adhesive 391 in the liquid phase, the first protrusion 373 is closer in the radial direction to the inner wall 317 than the first protrusion 373 is to the outer wall 318, as shown in FIG. 12. The first protrusion 373 is positioned so as to be closer to the inner wall surface 317 a than the first protrusion 373 is to the outer wall surface 318 a. The first protrusion 373 positioned as described above is inserted into the first recess 316 filled with the first adhesive 391 in the liquid phase.

Accordingly, the distance between the first lateral surface 373 a of the first protrusion 373 and the inner wall surface 317 a of the inner wall 317 in the radial direction is smaller than the distance between the second lateral surface 373 b and the outer wall surface 318 a of the outer wall 318. Moreover, since the inner wall 317 is taller than the outer wall 318 in the Z-direction as described above, the length in the Z-direction of the gap between the first lateral surface 373 a and the inner wall surface 317 a is larger than the length in the Z-direction of the gap between the second lateral surface 373 b and the outer wall surface 318 a.

Accordingly, when the first adhesive 391 in the liquid phase overflows from the first recess 316 due to the insertion of the first protrusion 373 into the first recess 316, the first adhesive 391 is likely to flow into the gap between the second lateral surface 373 b and the outer wall surface 318 a rather than the gap between the first lateral surface 373 a and the inner wall surface 317 a. The first adhesive 391 between the second lateral surface 373 b and the outer wall 318 flows upward toward the inclined part of the second lateral surface 373 b. The first adhesive 391 flows away from the central axis in the radial direction toward the outside of the housing space.

<Connection Between Second Recess and Second Protrusion>

Next, the connection between the second recess 374 of the connector 370 and the second protrusion 383 of the cover 380 through the second adhesive 392 will be described.

The second recess 374 is recessed from the upper support surface 371 c toward the lower support surface 371 d as shown in FIG. 11. The second recess 374 is defined by an inner surface 374 a, an outer surface 374 b, and a bottom surface 374 c connecting these two surfaces. The inner surface 374 a and the outer surface 374 b are aligned and spaced from each other in the radial direction.

The inner surface 374 a is closer to the central axis in the radial direction than the outer surface 374 b is to. The inner surface 374 a extends from the bottom surface 374 c in the Z-direction to be longer than the outer surface 374 b. A part of the inner surface 374 a close to the upper support surface 371 c does not overlap the outer surface 374 b in the radial direction.

The second protrusion 383 includes a third lateral surface 383 a, a fourth lateral surface 383 b, and a second tip surface 383 c connecting the third lateral surface 383 a and the fourth lateral surface 383 b. The third lateral surface 383 a and the fourth lateral surface 383 b are aligned in the radial direction. Each of these lateral surfaces has an annular shape. The third lateral surface 383 a is closer to the central axis in the radial direction than the fourth lateral surface 383 b is to.

The thickness between the third lateral surface 383 a and the fourth lateral surface 383 b in the radial direction is constant on the second tip surface 383 c side, but changes on the end 382 b side. That is, on the end 382 b side, the fourth lateral surface 383 b is inclined away from the third lateral surface 383 a such that the thickness between the third lateral surface 383 a and the fourth lateral surface 383 b gradually increases toward the end 382 b in the Z-direction.

The third lateral surface 383 a and the fourth lateral surface 383 b are farther from the central axis in the radial direction than the inner surface 374 a of the second recess 374 is from. The third lateral surface 383 a and the fourth lateral surface 383 b are closer to the central axis in the radial direction than the outer surface 374 b is to.

When the second protrusion 383 is inserted into the second recess 374 filled with the second adhesive 392 in the liquid phase, the second protrusion 383 is closer in the radial direction to the inner surface 374 a than the second protrusion 383 is to the outer surface 374 b, as shown in FIG. 13. The second protrusion 383 positioned as described above is inserted into the second recess 374 filled with the second adhesive 392 in the liquid phase.

Accordingly, the distance between the third lateral surface 383 a of the second protrusion 383 and the inner surface 374 a of the second recess 374 in the radial direction is smaller than the distance between the fourth lateral surface 383 b and the outer surface 374 b in the radial direction. Moreover, since the inner surface 374 a is longer than the outer surface 374 b in the Z-direction as described above, the length in the Z-direction of the gap between the third lateral surface 383 a and the inner surface 374 a is larger than the length in the Z-direction of the gap between the fourth lateral surface 383 b and the outer surface 374 b.

Accordingly, when the second adhesive 392 in the liquid phase overflows from the second recess 374 due to the insertion of the second protrusion 383 into the second recess 374, the second adhesive 392 is likely to flow into the gap between the fourth lateral surface 383 b and the outer surface 374 b rather than the gap between the third lateral surface 383 a and the inner surface 374 a. The second adhesive 392 between the fourth lateral surface 383 b and the outer surface 374 b flows upward toward the inclined part of the fourth lateral surface 383 b. The second adhesive 392 flows away from the central axis in the radial direction toward the outside of the housing space.

<Effects>

As described above, since the cover 380 is fixed to the motor 310 through the connector 370, the housing space is defined, and the control board 360 is housed in the housing space. The gap between the motor 310 and the connector 370 is sealed by the first adhesive 391, as well as the gap between the connector 370 and the cover 380 is sealed by the second adhesive 392. Accordingly, the sealing properties of the housing space can be improved. Therefore, the control board 360 is protected from dust, moisture, and the like.

As described above, the first adhesive 391 and the second adhesive 392 are adhered to the connector 370. The connector 370 has two bonded parts (sealing parts) bonded by the adhesives. These two sealing parts are aligned in the Z-direction. Accordingly, the sealing parts can be checked easily.

Further, the first recess 316 and the first protrusion 373 are connected by the first adhesive 391. The second recess 374 and the second protrusion 383 are connected by the second adhesive 392. As a result, the thickness of the adhesive between the housing space and the outside is thick. Accordingly, the sealing properties can be improved. Moreover, the strength of the physical connection between the motor 310 and the connector 370, and the strength of the physical connection between the connector 370 and the cover 380 are improved by anchor effect.

In the present embodiment, when the first protrusion 373 is inserted into the first recess 316 filled with the first adhesive 391 in the liquid phase, the first protrusion 373 is closer in the radial direction to the inner wall surface 317 a of the first recess 316 than the first protrusion 373 is to the outer wall surface 318 a. The inner wall surface 317 a is longer in the Z-direction than the outer wall surface 318 a.

Accordingly, when the first adhesive 391 in the liquid phase overflows from the first recess 316 due to the insertion of the first protrusion 373 into the first recess 316, the first adhesive 391 is likely to flow into the gap between the second lateral surface 373 b and the outer wall surface 318 a rather than the gap between the first lateral surface 373 a and the inner wall surface 317 a. That is, the first adhesive 391 in the liquid phase is likely to spread toward the outside rather than the housing space. Accordingly, the state of the first adhesive 391 located between the first recess 316 and the first protrusion 373 and sealing the gap therebetween can be visually checked easily from the outside of the housing space.

Similarly, when the second protrusion 383 is inserted into the second recess 374 filled with the second adhesive 392 in the liquid phase, the second protrusion 383 is closer in the radial direction to the inner surface 374 a of the second recess 374 than the second protrusion 383 is to the outer surface 374 b. The inner surface 374 a extends from the bottom surface 374 c in the Z-direction to be longer than the outer surface 374 b.

Accordingly, when the second adhesive 392 in the liquid phase overflows from the second recess 374 due to the insertion of the second protrusion 383 into the second recess 374, the second adhesive 392 is likely to flow into the gap between the fourth lateral surface 383 b and the outer surface 374 b rather than the gap between the third lateral surface 383 a and the inner surface 374 a. That is, the second adhesive 392 in the liquid phase is likely to spread toward the outside rather than the housing space. Accordingly, the state of the second adhesive 392 located between the second recess 374 and the second protrusion 383 and sealing the gap therebetween can be visually checked easily from the outside of the housing space.

According to the method of manufacturing the drive device 300, when connecting the motor 310, the connector 370, and the cover 380, these do not need to be reversed in the vertical direction. Accordingly, the manufacturing method can be simplified.

Although the present disclosure is described with reference to the preferred embodiment, the present disclosure is not limited to the above-described embodiment but may be implemented with various modifications without departing from the spirit of the present disclosure.

Additional advantages and modifications will readily occur to those skilled in the art. The disclosure in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. 

What is claimed is:
 1. A drive device comprising: a motor; a connector on which a control board configured to control the motor is mounted; a cover that defines a housing space for the control board together with the motor and the connector; a first adhesive that connects the motor and the connector; and a second adhesive that connects the connector and the cover, wherein the motor, the connector, and the cover are stacked with each other in a predetermined direction, the connector is between the motor and the cover in the predetermined direction, the motor has a first side on which the connector is mounted, the first side of the motor has a first recess recessed in the predetermined direction, the first recess having an annular shape that surrounds an imaginary line extending along the predetermined direction, the connector has a mounting side facing the motor, the mounting side of the connector has a first protrusion protruding toward the motor in the predetermined direction, the first protrusion having an annular shape corresponding to the first recess, the connector has a connection side facing the cover, the connection side of the connector has a second recess recessed in the predetermined direction, the second recess having an annular shape that surrounds the imaginary line extending along the predetermined direction, the cover has a rim side facing the connector, the rim side of the cover has a second protrusion protruding toward the connector in the predetermined direction, the second protrusion having an annular shape corresponding to the second recess, the first protrusion is inserted into the first recess, the first protrusion and the first recess are connected over an entire circumference of the first recess by the first adhesive, the second protrusion is inserted into the second recess, and the second protrusion and the second recess are connected over an entire circumference of the second recess by the second adhesive.
 2. A method of manufacturing a drive device, the drive device including: a motor; a connector on which a control board configured to control the motor is mounted; a cover that defines a housing space for the control board together with the motor and the connector; a first adhesive that connects the motor and the connector; and a second adhesive that connects the connector and the cover, the method comprising the successive steps of: placing the motor such that a first side of the motor on which the connector is to be mounted is positioned above a second side of the motor in a vertical direction; applying the first adhesive in liquid phase to a first recess formed on the first side of the motor, the first recess being recessed downward in the vertical direction and having an annular shape that surrounds an imaginary line extending along the vertical direction; inserting a first protrusion formed on a mounting side of the connector into the first recess, the first protrusion protruding downward in the vertical direction and having an annular shape corresponding to the first recess, and thereby the first protrusion and the first recess are connected over an entire circumference of the first recess by the first adhesive; applying the second adhesive in liquid phase to a second recess formed on a connection side of the connector that is an opposite side of the mounting side in the vertical direction, the second recess being recessed downward in the vertical direction and having an annular shape that surrounds the imaginary line extending along the vertical direction; and inserting a second protrusion formed on a rim side of the cover into the second recess, the second protrusion protruding downward in the vertical direction and having an annular shape corresponding to the second recess, and thereby the second protrusion and the second recess are connected over an entire circumference of the second recess by the second adhesive. 